I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
spars sparse spears spares spurs sparrows spiers spoors sprees sopors speers spires sprues spores sapors speirs sprays supers soapers spireas sapours suppers sappers sippers spurreys spurries spurious spiraeas saporous suppress sapphires spruce sprucy zappers zippers sporozoa superrace
pars spars papers capris mappers sappers wrappers rapers nappers keepers coppers lippers parrs parse pairs heapers rippers peppers coopers moppers pipers copras paras pares capers gapers japers lopers gippers sparse suppers yaupers shoppers tappers shapers chippers dopers wipers whoopers diapirs whappers uppers topers paris vapors tapers peepers soapers spares hopers cyprus zippers repairs spurs reapers quippers coppras hypers apres jeepers mopers gawpers kippers copers coappears cappers gyppers purs pears lappers sapors rappers loopers poppers loppers cuppers vipers appears hoppers beepers lepers sopors hoopers paupers pros knappers spears leapers reappears supers repros diapers boppers sippers cypres nippers ropers tapirs apers toppers zappers weepers whippers dippers whoppers cheepers dupers choppers shippers tippers yappers yawpers
spar spare sparrow sparry sprue supra spree spurrey spur spry spirea spray spiry spire spiraea spear spurry spore osprey